Lasers and X rays help to bring microscopic particles into focus in a University research lab.
The University Center for Ultrafast Optical Sciences has been working to produce a focused beam of X rays for use in atomic scale imaging.
A research team including electrical engineering professors Henry Kapteyn and Margaret Murname and fellows Andy Rundquist and Charles Durfee is attempting to provide an important step in improving detail when viewing cellular and molecular components.
"We're converting laser light from the near-infrared end of the spectrum to the X-ray of the spectrum," said Durfee, a University Electrical Engineering research fellow.
"We want X-ray and infrared to travel at the same speed," Durfee said. "We trap a laser beam in a capillary tube and speed it up to match the speed of an X-ray," Durfee said.
He added that this process generates a highly focused beam of X rays.
It has long been possible to generate X rays with lasers, but this research makes the process much more efficient. By shooting a rapidly pulsing laser through a hollow tube filled with gas, the device creates a beam with a shorter wavelength.
Shorter wavelengths allow for more detail in imaging.
"When using light to take pictures, the finest detail is determined by the wavelength of the light," Durfee said.
Traditional lasers emit light with wavelengths between the 500-1000 nanometer range.
But the University device creates wavelengths at about 20 nm, with the possibility of being as short as 2nm.
"Now we're working to make the wavelengths even shorter," Durfee said.
Dufee said with the increased detail afforded by the shorter wavelength, biologists and chemists will be able to see more detail about their microscopic subjects.
Another helpful advantage of laser light is its ability to make three-dimensional holograms.
"In bio-chem you could see 3-D pictures of DNA strands," Durfee said.
Engineering sophomore Karen Goldkind said she was impressed with the work being done at the University.
"You always think of the University of Michigan as being a leading institution in research," Goldkind said. Goldkind said she attended the University for the possibility of research in similar fields.
"That's one of the reasons I chose to come here," she said.
University engineers at CUOS are working on some of the most advanced laser technologies available today, including femtosecond lasers which generate the shortest, most intense bursts of energy yet produced.
07-06-98
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